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Stabilization of the KSTAR Power System for the First Plasma Operation
Jong-Dae Kong,Seong-Lok Hong,In-Sung Hwang,Jae-Hoon Choi,Chang-Hwan Kim,Dong-Keun Lee,Yaung-Soo Kim,Myeun Kwon,Byung-Ju Park,Hang-Kyu Yoo IEEE 2010 IEEE transactions on plasma science Vol.38 No.9
<P>After more than ten years of construction, the Korea Superconducting Tokamak Advanced Research (KSTAR) device finally completed its assembly in June 2007. We conducted the first plasma operation from April 2008 to July 2008 and succeeded in the plasma generation in July 2008. The electric power system for the first plasma operation is made up of various electric devices, including 154-kV circuit-breaker systems, a 154/22.9-kV 50-MVA transformer, 22.9-kV circuit-breaker systems, and reactive power compensator (RPC) and harmonic filter (HF) systems. When the poloidal-field magnet power supplies were operated, the reactive power and harmonic currents (12n ± 1) were generated instantaneously in the KSTAR electric power system for the first plasma generation due to the characteristics of the KSTAR superconducting coils. The measured voltage drop and harmonics seriously affected the other experimental equipment as well. Therefore, it is important to compensate the reactive power and remove the harmonics with the RPC and HF system for the superconducting tokamak device. In this paper, we discuss the stability of the electric power system and the operational results of the RPC and HF systems during the KSTAR first plasma operation. Furthermore, the upgrade plan of the electric power system based on the KSTAR operation plan will be discussed.</P>
공종대(Jong-Dae Kong),홍성록(Seong-Lok Hong),황인성(In-Seong Hwang),김양수(Yaung-Soo Kim),엄대영(Dae-Young Eom) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
핵융합반응은 초고온의 플라즈마 상태에서 가벼운 원자핵들이 융합하여 무거운 원자핵으로 바뀌는 현상으로, 이 과정에서 감소된 질량이 막대한 에너지로 변환되는데 이를 핵융합에너지라고 한다. 핵융합에너지는 인류의 에너지 위기를 극복할 수 있는 최적의 대체에너지이며, 무한, 청정, 고효율에너지이다. 이에 국가핵융합연구소(NFRI)는 Green Energy 의 개발과 핵융합에너지 상용화 기술을 개발하기 위해 핵융합연구장치인 KSTAR(Korea Superconducting Tokamak Adavanced Research)를 제작하여 장치의 운전연구 및 기술 확보에 힘을 쏟고 있다. 또한 핵융합 관련 파생기술을 활용한 첨단 신사업 창출에 기여하고 있다. 본 논문에서는 KSTAR 1st Plasma 실험 시 KSTAR 장치에 전력을 공급하기 위한 전력설비 현황, 전력품질분석, 전력사용량 분석을 통해 향후 KSTAR 장치 운전을 위해 필요한 수전설비 증설, 무효전력보상장치 증설 등과 같은 전력계통의 효율화와 안정화를 위한 개선사항에 대해 기술하였다.
Kong, Ho-Youl,Chung, Dae-Sung,Kang, In-Nam,Lim, Eun-Hee,Jung, Young-Kwan,Park, Jong-Hwa,Park, Chan-Eon,Shim, Hong-Ku Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.11
Two fluorene-based conjugated copolymers containing hexyl-thiophene derivatives, PF-1T and PF-4T, were synthesized via the palladium-catalyzed Suzuki coupling reaction. The number-average molecular weights (Mn) of PF-1T and PF-4T were found to be 19,100 and 13,200, respectively. These polymers were soluble in common organic solvents such as chloroform, chlorobenzene, toluene, etc. The UV-vis absorption maximum peaks of PF-1T and PF-4T in the film state were found to be 410 nm and 431 nm, respectively. Electrochemical characterization revealed that these polymers have low highest occupied molecular orbital (HOMO) levels, indicating good resistance against oxidative doping. Thin film transistor devices were fabricated using the top contact geometry. PF-1T showed much better thin-film transistor performance than PF-4T. A thin film of PF- 1T gave a saturation mobility of 0.001-0.003 cm2 V?1 s?1, an on/off ratio of 1.0 × 105, and a small threshold voltage of ?8.3 V. To support TFT performance, we carried out DSC, AFM, and XRD measurements.
New selenophene-based semiconducting copolymers for high performance organic thin-film transistors
Kong, Hoyoul,Chung, Dae Sung,Kang, In-Nam,Park, Jong-Hwa,Park, Moo-Jin,Jung, In Hwan,Park, Chan Eon,Shim, Hong-Ku Royal Society of Chemistry 2009 Journal of materials chemistry Vol.19 No.21
<P>A series of new selenophene-based organic semiconducting copolymers, poly(5,5′-bis(3-dodecylthiophen-2-yl)-2,2′-biselenophene) (<B>PDT2Se2</B>) and poly(5,5′-bis(4,4′-didodecyl-2,2′-bithiophen-5-yl)-2,2′-biselenophene) (<B>PDT4Se2</B>), were successfully synthesized by Stille and oxidative coupling reactions. Our aim was to investigate the effects of the selenophene units and inserted dodecylthiophenes on the optical and electrochemical properties of these copolymers, their intermolecular ordering in the film state, and hence their thin-film transistor (TFT) performance. X-ray-diffraction (GIXRD and XRD) and theoretical calculations for models of these polymers were used to show that <B>PDT2Se2</B> films have well organized interlayer packing and π–π stacking, whereas the films of <B>PDT4Se2</B>, which contain regioregularly inserted additional dodecylthiophenes next to the repeat units of <B>PDT2Se2</B>, have a long-range amorphous structure. The TFT characteristics of these polymers are strongly dependent on the intermolecular ordering of the polymer chains. <B>PDT2Se2</B> exhibited a high hole transporting mobility of 0.02 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> due to its excellent intermolecular ordering, whereas <B>PDT4Se2</B> exhibited a very poor mobility of 1.4 × 10<SUP>−5</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> due to its amorphous characteristics, which result from the repulsion between the additional dodecylthiophenes. These results confirm that it is important to consider intermolecular ordering in the design of semiconducting materials for high performance OTFTs.</P> <P>Graphic Abstract</P><P>A series of new selenophene-based organic semiconducting copolymers were synthesized by Stille and oxidative coupling reactions, one of them, poly(5,5′-bis(3-dodecylthiophen-2-yl)-2,2′-biselenophene), exhibiting a mobility of 0.02 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> due to its excellent intermolecular ordering. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b823082j'> </P>
A New Amorphous Semiconducting Polythiophene for High-Performance Organic Thin-Film Transistors
Kong, Hoyoul,Lee, Dong Hoon,Seo, Jung-In,Oh, Ji-Young,Chung, Dae Sung,Park, Jong-Won,Kwon, Soon-Ki,Lee, Yoon Sup,Park, Chan Eon,Shim, Hong-Ku American Chemical Society 2010 ACS APPLIED MATERIALS & INTERFACES Vol.2 No.4
<P>A new amorphous semiconducting polymer containing dodecylthiophene rings and a rigid thieno[3,2-<I>b</I>]thiophene ring, poly(2,5-bis(3′-dodecyl-2,2′-bithiophen-5-yl)thieno[3,2-<I>b</I>]thiophene) (<B>NAP</B>), was synthesized via a microwave-assisted Stille coupling reaction. The presence of the flexible unsubstituted thiophene ring units next to the rigid fused thiophene ring caused <B>NAP</B> to have an amorphous structure. This structure was confirmed by XRD, AFM, and computational calculations. In particular, the out-of-plane XRD patterns of <B>NAP</B> thin films exhibited no reflection peaks before or after the annealing process, indicating that the films had amorphous microstructures. In addition, AFM images of the <B>NAP</B> thin films showed amorphous surface morphologies with very small root-mean-square (rms) surface roughnesses of 0.3−0.5 nm, independent of surface treatment or heat treatment. Computational calculations performed to investigate the preferred conformation of the polymer confirmed the amorphous characteristics of the <B>NAP</B> structure. On the basis of these findings, we propose how an amorphous <B>NAP</B> semiconductor can maintain high carrier mobility. A <B>NAP</B>-based TFT device exhibited a very high carrier mobility of 0.02 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> with an on/off ratio of 1 × 10<SUP>5</SUP> and a very small threshold voltage of −2.0 V. This carrier mobility is the highest yet reported for TFTs based on amorphous semiconductors. Thus, the present findings suggest that an amorphous semiconductor layer comprised of <B>NAP</B> would be suitable for use in high-performance organic TFTs fabricated via simple processes in which neither surface treatment nor heat treatment is necessary.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2010/aamick.2010.2.issue-4/am9008852/production/images/medium/am-2009-008852_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am9008852'>ACS Electronic Supporting Info</A></P>
Jong-Ho Choi,Sang-Uk Han,Han-Kwang Yang,Young-Woo Kim,Keun Won Ryu,Joong-Min Park,Ji Yeong An,Min-Chan Kim,Sungsoo Park,Kyo Young Song,Sung Jin Oh,Seong-Ho Kong,Byoung Jo Suh,Dae Hyun Yang,Tae Kyung H 대한외과학회 2020 Annals of Surgical Treatment and Research(ASRT) Vol.99 No.5
Purpose: Quality of life (QOL) has become important in the trend of emphasizing patient satisfaction. This study aimed to evaluate the QOL in patients who underwent laparoscopic or robotic gastrectomy for gastric cancer. Methods: A prospective trial was performed involving patients who underwent laparoscopic or robotic gastrectomy for primary gastric cancer at 11 hospitals in Korea. Within this comparative trial, QOL, postoperative pain, and long-term complications were exanimated. The quality-of-life questionnaire (QLQ)-C30 and QLQ-STO22 developed by the European Organization for Research and Treatment of Cancer were used for the QOL survey. We compared the data after dividing it into several types of characteristics as follows; device (robotic or laparoscopic), operation type, pathological stage, and sex. Biased components were extracted by logistic regression analysis. Propensity score matching was applied to the data set with the biased components. Results: In total, 434 patients (211 for laparoscopic surgery and 223 for robotic surgery) were enrolled, out of which 321 patients who responded to both preoperative and postoperative surveys were selected for analysis. Robotic gastrectomy was not different from laparoscopic gastrectomy with respect to postoperative QOL. Distal gastrectomy showed better scores than total gastrectomy in terms of role functioning, social functioning, fatigue, nausea/vomiting, pain, dyspnea, constipation, financial difficulties, dysphagia, eating restrictions, anxiety, taste, and body image. Male patients showed better scores on the 19 scales compared to female patients. Conclusion: Robotic and laparoscopic approaches for gastric cancer surgery did not differ from each other with respect to QOL. Distal gastrectomy resulted in better QOL than total gastrectomy.
공대영 ( Dae Young Kong ),은덕수 ( Duk Soo Eun ),배영호 ( Young Ho Bae ),이종현 ( Jong Hyun Lee ) 한국센서학회 2005 센서학회지 Vol.14 No.3
N/A The SOI structure with buried alumina was fabricated by ALD followed by bonding and etchback process. The interface of alumina and silicon was analyzed by CV measurements and cross section was investigated by SEM analysis. The density of interface state of alumina and silicon was 2.5E11/cm²-eV after high temperature annealing for wafer bonding. It was confirmed that the surface silicon layer was completely isolated from substrate by cross section SEM and AES depth profile. The device on this alumina SOI structure would have better thermal properties than that on conventional SOI due to higher thermal conductivity of alumina than that of silicon dioxide.